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Re: Secondary size



Brian,
Most will probably tell you that your system is overcoupled. They're also
right
in most instances. Your description ("arcing from top to bottom and all around
the secondary") pretty much tells the story. When you fire it up, and see the
first sign of this, it's time to power down! John Corture's program uses
information from many coils to design in coupling. Most either build under of
over coupled systems to some degree. The fact is, once it's built, it's built!
Therefore, many will increase primary to secondary spacing by raising the
secondary up a bit until the sparkover's stop. I don't want to get into the ol
"raising the secondary" discussion again, as there is a lot of info in the
archives if your curious, but I think it is worth mentioning the fact that
what
you are getting is an overcoupled sparkover and what many have done to resolve
it.

Bart

Tesla List wrote:

> Original Poster: bhelms-at-dialpoint-dot-net (Brian Helms)
>
> I built a secondary that was 500 turns of #22 enameled wire on a 8 inch form
> and it didn't work at all.  I couldn't insulate between turns enough to keep
> it from arcing from top to bottom and all around on the secondary.  It did
> put on a heck of a show before it started smoking though.
>
> Brian Helms
> (KD4RLD)
>
> -----Original Message-----
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
> Date: Saturday, October 17, 1998 6:26 PM
> Subject: Re: Secondary size
>
> >Original Poster: Hollmike-at-aol-dot-com
> >
> >In a message dated 10/16/98 5:49:53 AM Mountain Standard Time,
> >tesla-at-pupman-dot-com writes:
> >
> >> Knowing this length you can design a
> >>  secondary coil that will give you the maximum inductance without
> >>  overloading the power transformer.
> >John C.,
> >   Based on the Wheeler equation, the maximum inductance of a coil with a
> >given length of wire occurs when the radius/winding length is 1.1111(or
> 10/9).
> >That would produce a very short, fat coil that would not necessarily be the
> >best geometry for a TC secondary.  Tesla did use coils that were relatively
> >short, with a large radius, but I believe he found it necessary to space
> wind
> >the coils to prevent excessive voltage stresses between the turns.
> >   Has anyone built a coil with such a geometry?  If so, how did it work?
> >MIke
> >
> >
> >